I've done a quick web search and came across this from the Aviation Consumer Action Project:

http://www.acap1971.org/director/dir...lay.cfm?DMID=1

"Major credit cards such as VISA, Master Card, and American Express will credit your account if the vendor of the product or service you purchased defaults by failing to deliver. However, this may not hold where an airline is already in bankruptcy at the time of purchase. As of this writing American Express has advised ACAP that it will not credit holders accounts for defaults on US Airways tickets,...."


Since National was in bankruptcy court for two years, can we assume Amex had the same policy towards them.